抄録
Various adaptive controls were suggested up to now. However, the adaptive controls are not widely recognized as practical control method. Practical adaptive control is thought to be established successfully by being only provided two suitable elements, one of which is robust and adaptive estimation corresponding to a system signal aspect and the other is feedback control applied with less exceptinal treatment even for nonminimum phase and/or delay system. After an daptating period, the two elements adaptive control can guarantee good performance, but in the period, often raises extreme action. This paper deals with the suitable estimation and feedback control, and improvement of control action in the adapting period by setting a control target in a zone instead of a point.